Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
J Endourol. 2013 Mar;27(3):366-9. doi: 10.1089/end.2012.0203. Epub 2012 Nov 7.
The intent of this study was to compare urine parameters between kidney stone formers with low, expected, and high creatinine to weight ratio (Cr/kg) and to discuss implications for treatment.
In this retrospective study, 381 stone formers (205 females and 176 males) with urine collections for nephrolithiasis evaluation were included. Using the first collected sample, patients were grouped into low, expected, and high Cr/kg using sex appropriate reference ranges (15.0-20.0 mg/kg for females and 18.0-24.0 mg/kg for males) and evaluated.
Of initial collections, 50.7% were outside the Cr/kg reference range. Median age increased as Cr/kg decreased with 13 years age difference between low (56) and high (43) groups. Body mass index and weight also increased significantly with decreased ratio. No significant difference between groups was found for urine volume, total oxalate, oxalate concentration, pH, and supersaturations of calcium oxalate and uric acid. Total calcium, sodium, citrate, calcium concentration, supersaturation of calcium phosphate, and other parameters significantly increased with increased Cr/kg for the cohort.
To our knowledge, this is the first study to thoroughly evaluate the impact of Cr/kg on urine parameters. Clinicians should be cognizant of limitations of Cr/kg for evaluating collection adequacy. It is especially important to consider Cr/kg when there is potential for undertreatment or overtreatment of patients with abnormal Cr/kg. Studies demonstrating hypercalciuria and high Cr/kg may need to be repeated before starting thiazide diuretics. Further studies are needed to determine how to better interpret urine components that vary with Cr/kg ratio.
本研究旨在比较低、预期和高肌酐与体重比（Cr/kg）的肾结石患者的尿液参数，并讨论其对治疗的影响。
在这项回顾性研究中，纳入了 381 名接受肾结石评估尿液采集的结石形成者（205 名女性和 176 名男性）。使用首次采集的样本，根据性别适当的参考范围（女性 15.0-20.0mg/kg，男性 18.0-24.0mg/kg）将患者分为低、预期和高 Cr/kg 组进行评估。
初始采集的样本中，50.7%超出了 Cr/kg 参考范围。Cr/kg 越低，中位数年龄越大，低（56 岁）和高（43 岁）组之间相差 13 岁。体重指数和体重也随着比值的降低而显著增加。各组之间的尿体积、总草酸盐、草酸盐浓度、pH 值以及草酸钙和尿酸的过饱和度均无显著差异。对于队列中的所有参数，总钙、钠、柠檬酸盐、钙浓度、磷酸钙过饱和度以及其他参数均随着 Cr/kg 的增加而显著增加。
据我们所知，这是第一项全面评估 Cr/kg 对尿液参数影响的研究。临床医生应认识到 Cr/kg 评估收集充分性的局限性。在存在潜在治疗不足或过度治疗 Cr/kg 异常患者的情况下，尤其应考虑 Cr/kg。在开始噻嗪类利尿剂之前，可能需要重复进行显示高钙尿症和高 Cr/kg 的研究。需要进一步研究如何更好地解释随 Cr/kg 比值变化的尿液成分。
